Within the scope of footwear, and more specifically of soles for same, one of the solutions normally used is that in which the sole is obtained by means of injection moulding from elastomeric materials.
The outsoles are manufactured according to pre-established sizes, based on a stepped table of foot lengths, such that any person can find shoes in the market with a size suited to the length of his feet.
The same does not apply regarding the transverse elevation, as this is usually fixed for a certain type or design of footwear, which as is known means a serious problem for those having “wide feet”, who are forced to bear the discomfort of shoes which “pinch them” or are forced to use a larger size than they should depending on the length of the foot, because evidently as the size of the footwear increases, the width thereof increases in parallel.
The solution to this problem is to use lasts of different widths, this evidently having very negative effects from an economic point of view, specifically from the point of view of manufacturing and distribution costs.
A less encumbering solution is to use uppers based on soft materials, which partially resolves the problem, especially when the user's feet are not much wider than normal, but this leads to a deformation of the footwear making it lose its original appearance completely after a short period of use.
On the other hand, due to their very nature, these elastomeric soles offer virtually no degree of transpiration, such that they retain the user's body sweat, it thus being desirable to have an inner ventilation of the footwear for evaporating the sweat as it is produced.
Footwear provided with means of inner ventilation exists on the market, but the solutions adopted up to the present are structurally complex and functionally rather ineffective, thus their practical use is determined more by advertising propaganda than by a real effectiveness to that respect.